The present invention relates generally to hand-held communication devices such as mobile telephones, palmtop computers, personal digital assistants (PDA's) or the like, and more particularly, to an optical joystick for hand-held communication devices.
Hand-held communication devices, particularly mobile telephones, personal digital assistants (PDA's), and the like, comprise a class of portable electronic devices, whose size enables them to be held in one hand while being operated with the other. Typical hand-held communication devices include a display, which may include a digitizer or touch sensitive overlay for allowing a user to enter information and commands using a stylus or pen, and a keypad for entering alphanumeric text, common commands, selecting menus to be displayed by the display, and the like. Often, such hand-held communication devices include a small digital camera, allowing the user of the device to take digital photographs, which may be stored in the device's memory, and transmitted to others via a communication network.
Many hand-held communication devices support sophisticated software applications such as address book and calendar software, Internet browsers, text messaging, and the like. Such software applications require graphical user interface software employing a cursor for selection of menu items, entering of commands, and the like. Many hand-held communication devices further support gaming applications for the entertainment of their users. Such gaming applications often employ characters that must be precisely manipulated while playing the game.
Controls provided by hand-held communication devices (i.e., the keys of the keypad, the stylus/digitizer, and the like) do not readily allow accurate manipulation of indicia such as a cursor or gaming character, since the controls are clumsy to use and do not support true 360 degree movement of the indicia. Moreover, control devices such as mouses, trackballs, joysticks, and the like typically employed by computers are too bulky for use with hand-held communication devices due to the small size of the devices. As a result, users often find software or gaming applications supported by the hand-held devices difficult to use, lessening the utility of the devices to the user.